The park takes its name from a body of water that no longer exists. The Taijiang Lagoon formed a natural harbor along the southwestern coast of Taiwan, and by the 17th century it had become a hub of maritime activity — the Dutch East India Company established Fort Zeelandia on its shores, and Fujianese fishing communities settled around its edge. Then the rivers began doing what rivers do: depositing silt, building delta, slowly displacing the sea. By the late 18th century the lagoon had largely filled in. The land it left behind passed through centuries of agricultural use — rice paddies, aquaculture ponds, salt production — before anyone thought to ask what ecological value those wetlands held. The park established on October 15, 2009 was partly an answer to that question, and partly an acknowledgment that coastal habitats don't protect themselves.

Taijiang National Park covers 393.1 square kilometers in total, but the breakdown is revealing: only 49.05 square kilometers is land. The rest — 344.05 square kilometers — is a long coastal marine zone stretching 54 kilometers from the Yanshui River mouth to Dongji Island, extending to the 20-meter depth isobath offshore. That strip of nearshore water is not empty or incidental. It connects to the tidal mudflats and mangrove edges that make the park work as a habitat. The westernmost point of the main island of Taiwan, marked by the Guosheng Port Lighthouse, falls within the park's boundaries. The park runs 20.7 kilometers from north to south — not a vast expanse by national park standards, but its narrow coastal profile holds an outsized ecological punch.

Taijiang sits along the East Asian-Australasian Flyway, one of the world's great migratory corridors, and the wetlands here serve as critical stopover habitat for shorebirds and waterfowl crossing between breeding grounds in the north and wintering areas in the south. The intertidal mudflats offer feeding grounds for species traveling thousands of miles. Mangrove forests line the inner edges of the wetlands, providing nursery habitat for fish and shelter for nesting birds. The fish ponds and tidal channels that remain from earlier aquaculture use have been incorporated rather than erased — managed now to balance human use with wildlife needs. Walking the elevated boardwalks that thread through the mangroves in the early morning, with herons picking their way through shallow channels and egrets dotting the mudflats, is to witness the logic of a landscape that has been many things and is still becoming.

The coastline here carries centuries of layered human history. The Dutch-era Fort Zeelandia stood near what is now Tainan city, at the edge of the old lagoon. Later, the same wetlands that the Dutch saw as a harbor became the salt-producing flats that supported Tainan's economy for generations. The Cigu salt fields — among the most productive in Taiwan — once spread across what is now part of the national park's buffer area. As salt production declined in the late 20th century, those vast flat expanses became available for ecological restoration. The park's founding in 2009 reflected a broader recognition in Taiwan that coastal ecosystems had been eroded — not just by sediment, but by development — and that recovery required active commitment.

What makes Taijiang unusual among national parks is that much of it is in the process of being reclaimed by nature rather than simply preserved. Former aquaculture ponds are being converted back to tidal wetlands. Mangrove forests, once cleared for agriculture, are spreading again. Black-faced spoonbills — among the world's rarest large wading birds — winter here in internationally significant numbers, using the shallow lagoons and fish ponds as feeding territory. The park is not pristine wilderness; it never will be. Too much happened here across too many centuries for that kind of fiction. What it is, instead, is a working coast where fishermen still cast nets and conservation managers still move dikes — a place negotiating, season by season, between what was lost and what might be recovered.